Audio guy recording very low levels

A

analog_addict

Well-known member
Hello,

I've just done a short film and the audio guy has recorded all the dialogue at a very low level. His reasoning is that it's better to record low levels and pull it up in post (pro-tools). This way there is less noise.

I have always recorded dialogue between -12 and -6dB and the results are always good. I've had a listen through the audio files that the sound guy recorded and they are very very low. I'm worried.

He is adamant that it's all done in post and it will sound brilliant. When bringing up very low audio levels you will increase noise and increase muddiness.

Does anyone purposely record low level dialogue? It seems nuts and risky to me.
 
Does anyone purposely record low level dialogue?
- Only if an excessive amount of headroom is needed. Normal peaks of -6dB to -12dB (with a limiter) is adequate. Low levels 'can' be normalized, but this will bring up the pre-amp and other unwanted noise just the same. If it's 24 bit, the normalization process (increasing the level) should not add any audible noise... if.. the A/D converters are decent.. another reason to stay away from budget gear.
 
analog_addict said:
I've just done a short film and the audio guy has recorded all the dialogue at a very low level. His reasoning is that it's better to record low levels and pull it up in post (pro-tools). This way there is less noise.
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This makes absolutely no sense. Hopefully he's using a professional recorder with a low "self" noise-floor, or your goose is cooked.

Most consumer/prosumer recorders have a "self" noise-floor between -60 to -80 dB RMS, while pro gear is often -100 dB RMS or better.

Do you know what audio recorder your audio guy was using ?
 
Noise wouldn't be my biggest concern here, especially if the audio has been recorded on a budget recorder and/or at 16-bit. If he recorded at 16-bit, the levels may be brought up in post but the signal will fall apart if there is any modest amount of post-processing (EQ, compression, limiting) applied. If the sound person in question had the foresight to record in 24-bit, that will help, but it's still a risk if the levels are too low.
 
My first choice would be to fire him and get someone who knows what they are doing.

That is probably not an option, unfortunately.

No he is most certainly NOT correct. You want to record as hot as you can. That usually translates to the dialog around -12, sometimes you can get hotter, but since you never really know when some actor is going to get inspired to do something loud you can get in trouble pushing it past that with out really good limiters.

I do mostly post so I get junk tracks like that all the time, well a lot more often than I would like.
Post has two big issues generally with very low tracks.

First recording low and cranking up the headphone amps gives him a distorted impression of what he is recording. Headphone amps are often fairly noisy so he is probably missing a bunch in the noise that he is sure is going to go away in post. Some will, the headphone amp noise is not recorded, but most will still be there.

He is also throwing away bits. So the tracks are going to come out effectively at a much lower bit rate. What happens when you try to clean up the tracks is they (to use a video term) fall apart. *** Just noticed Alex said the same thing, maybe it's not a video term*** Things get gritty very fast. And the noise is still there and when I have to raise the level it raises the noise also. If it's going to be noisy for some reason I want hot tracks so the Noise reduction software has some bits to chew on.

I was on early enough on one short where the guy was pulling this stuff. didn't have wireless and told them that his shot gun from 100 feet or so on the long shot was going to work. I knew the line producer and he asked me to look at some of the raw files, I couldn't even see a waveform in Protools till I zoomed way in. The whole scene needed ADR, and the producer went out and bought wireless and ran those to a separate recorder for the rest of the shoot. In the end I don't think we used more than a minute or two of the "official" sound recordings.

That "recordist" also liked to tape handheld recorders all over the place. So I got sometimes six or more tracks from a shot, all pretty much junk except for the lavs.
 
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analog_addict said:
He is adamant that it's all done in post and it will sound brilliant.
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Let me guess. HE is NOT doing the post here.
I would even guess that he has NEVER done post with that kind of working theory.
Sounds like it is too late to fire the guy and find someone who knows what they are doing.
Dare him to come here and defend his premise.
 
So, this topic got me wondering, does noise from analog gain typically scale linearly in most devices?
 
When you say levels are "very very low", how low are the levels actually? A number would help us give you a better idea of how difficult it will be to work with in post.
 
CF01 said:
does noise from analog gain typically scale linearly in most devices?
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From my experience I would say YES for the higher end audio recorders, and NO for the lower end recorders.

For example, applying 20 dB Gain with a Sony PCM-M10 recorder caused the noise floor to go from -75 dB RMS to -50 dB RMS. ( the noise-floor of the recorder was very audible at -50 dB )

With a higher end recorder the noise-floor might be -100 dB RMS or better, so boosting the gain by 20 dB still puts the recorded noise-floor way beyond the audible range. ( this is the "self" noise of the recorder, not the ambient noise level of the room which is something completely different )
 
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